Precious metals, predominantly gold, are the bases for the principal alloys used in dental restorations. These alloys are costly and for continued effective use of these metals, it must be assured that maximum performance is obtained per dollar of precious metal content. The principal properties of interest are strength and tarnish resistance. To obtain a basic understanding of the interrelation of these properties with alloy composition, a systematic study of the Au-Ag-Cu and Au-Ag-Cu-Pd systems will be carried out. The initial study will focus on the tarnish behavior of a set of alloys covering the ternary system as determined by in vitro tarnish testing. These alloys with minimum gold and acceptable tarnish resistance will be studied in greater detail, involving analysis of microstructure, hardening mechanisms and the effect of replacing gold with palladium. The processing of alloys will be designed to be compatible with dental laboratory procedures. The in vitro testing is designed to be compatible with possible future in vivo evaluation of selected compositions.